Electronic displays have grown in popularity not only for indoor use, but also for outdoor use. One exemplary application, without limitation, is the digital out of home market where the electronic displays are increasingly replacing the use of static posters. The use of electronic displays is advantageous because they allow images to be changed quickly as well as permit the use videos and interactive displays, among other benefits. Such displays may be used for advertisements, public announcements, information, wayfinding, and the like.
Such outdoor, and some indoor, displays are sometimes encased in a housing to protect them from environmental conditions. The housing may be designed to resist, mitigate, manage, control, or prevent water, precipitation, dust, and air contaminant intrusion, vandalism, tampering, wind, temperature changes, solar loading, extreme temperatures, and the like. Oftentimes, these displays are placed outdoors where they are subject to extreme temperatures, drastic temperature changes, and significant solar loading. If the temperature inside the housing gets too high or too low the electronic displays and related components may be damaged. As such, the temperature inside the housing must be maintained at acceptable levels. In order to maintain the temperature inside the housings at acceptable levels, a number of gas pathways are generally placed through the housing. Sometimes, a combination of open loops carrying ambient air and closed loops carrying circulating gas are used.
Over time, the market has demanded increasingly larger displays. These larger displays have correspondingly larger surface areas and often require correspondingly larger, in size or number, gas pathways to maintain the temperature in the housing. As the dimensions of these displays and corresponding gas pathways have increased, the potential for the displays to bow outwardly has increased. This is because, typically, the displays are mostly unsupported. The displays are generally mounted along their perimeter so illumination from the backlight is permitted to reach the entirety of the display, among other considerations. Thus, a large section of the display is not directly mounted to a housing or other stabilizing or supporting structure, which may allow bowing of the display. Additionally, the asymmetrical temperature loading of various layers and components of the display may contribute to such display bowing. Further still, some displays have a gap between the electronic display itself and a cover panel located in front of the electronic display. As the electronic display bows towards the cover panel, the gap between the cover panel and the display may be narrowed and a resulting venturi effect may be created. The venturi effect may increase the bowing forces.
Such bowing can cause damage to the display, distortion of the displayed image, and may disrupt airflow through the open and closed loops. In some cases, the electronic display may bow outwardly enough that it contacts the cover panel. This may not only interrupt normal thermal management but may also result in significant heat transfer from the solar loaded cover panel to the electronic display. This may rapidly cause permanent damage to the display. Therefore, what is needed is a system and method for reducing or combating bow in an electronic display.
Additionally, display assemblies comprising a backlight sometimes have a sealed cavity for the backlight. As the illumination devices and other components of the backlight generate heat, heat can become trapped in this cavity. Because the cavity may be completely or partially sealed, the heat may build up and cause damage to components of the assembly. Therefore, what is needed is a system and method for removing heat from the backlight cavity.
The present invention is a system and method for reducing or combating bow in an electronic display. The present invention is also a system and method for removing heat from the backlight cavity. The present invention provides a first gas pathway through first gas pathways between a cover panel and an electronic display and an additional flow path through a backlight cavity located in the space between the electronic display and a backlight. The flow of air through the backlight cavity removes heat from the backlight cavity generated by the illumination devices or other components.
The amount or speed of airflow through the first gas pathway and the backlight cavity may be controlled so as to create a pressure drop in the backlight cavity as compared to the first gas pathway. This pressure drop may result in forces which tend to pull the electronic display away from the cover panel, thereby reducing or eliminating the bowing. In particular, a support or a bracket may be used to create an entrance gap and exit gap into and out of the backlight cavity. In this way the amount or speed of airflow through the backlight cavity may be controlled. The entrance gap may be smaller than the exit gap. In exemplary embodiments, an angled section may extend from the distal end of the bracket located near the exit gap. The angled section may extend towards the side of the housing to restrict the flow of air from the first gas pathway into a second gas pathway located behind the backlight. The constriction of this air may create a venturi effect, creating a low-pressure zone near the angled section to pull circulating gas through the backlight cavity.